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Biomedical subjects

I Dyrda

Publications and source records attributed to I Dyrda.

At least 37 records · Page 2Linked to original sources
PubMed1991

[Effect of subvalvular disease on results of percutaneous mitral valvotomy].

In order to study the results of percutaneous mitral valvuloplasty (PMV), subvalvular mitral disease was classified using: 1) the transthoracic echo score (0-4), 2) an index derived from left ventricular angiography defined as the ratio of the distance from the extremity of the papillary muscle and the mitral valve in systole and the distance between the beginning of the aortic root and the apex of the left ventricle in diastole. This index of subvalvular fibrosis could be measured in 80 out of our first 103 PMV performed without complication; the mitral surface are a increased from 1.1 +/- 0.4 to 2.2 +/- 0.8 cm2 (p less than 0.0001). After PMV, mitral regurgitation was observed or was aggravated in 28 patients (35%), by one grade in 25 and by more than one grade in 3. The overall echo score was 8.3 +/- 1.5 and that of subvalvular fibrosis was 2 +/- 0.6. The angiographic index of subvalvular fibrosis was 0.18 +/- 0.04. No correlation was observed between echo and angiographic appreciation of subvalvular fibrosis. Multivariate analyses were selected: 1) the overall echocardiographic score (r = -0.45, p less than 0.0001), but not the angiographic index of subvalvular fibrosis or echocardiographic score of subvalvular fibrosis, was predictive of increase of valve surface area; 2) the absence of mitral regurgitation before PMV (p less than 0.01) and an angiographic index of subvalvular fibrosis less than or equal to 0.15 (p less than 0.03) were predictive of increased mitral regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

[Immediate results and mid-term follow-up after percutaneous mitral valve replacement].

Percutaneous mitral valvuloplasty (PMV) was performed by the anterograde transseptal approach (double balloon technique) in 154 patients with symptomatic mitral stenosis. The mean age of the patients was high (53 +/- 14 years), 87% were women, 68% were in functional Classes III or IV of the NYHA and 37 (24%) had previously undergone surgical commissurotomy. The echocardiographic score was 8.5 +/- 1.6. PMV could not be completed because of a technical failure or a complication in 14 cases (9%). In the other patients, PMV increased mitral surface area from 1.0 +/- 0.3 to 2.0 +/- 0.8 cm2 (p less than 0.0001). A haemodynamic success (greater than or equal to 25% increase in mitral surface area and final area greater than or equal to 1.5 cm2) was obtained in 104 patients (75%). The predicting factors of success were echocardiographic score (8.1 +/- 1.4 versus 9.4 +/- 1.7; p less than 0.0001) and cardiac output (4.0 +/- 1.1 versus 3.0 +/- 1.0/l/min; p less than 0.0001). The duration of the procedure, the technical failure rate and the frequency of cardiac perforation were influenced by the learning curve. The degree of mitral regurgitation increased after PMV in 34% of cases, usually by one grade and without clinical or haemodynamic consequences. Acute mitral regurgitation was a rare (3%) and impredictable complication. An interatrial shunt was demonstrated in 80% of cases after PMV but the Qp/Qs ratio rarely exceeded 1.5 (11%). This shunt disappeared or decreased in the majority of cases during follow-up. The clinical result was an improvement of at least one functional Class in 83% of cases at 6 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Accelerated coronary atherosclerosis after cardiac transplantation: major threat to long-term survival.

Accelerated coronary atherosclerosis (ACA) has been documented at autopsy and was noted at coronary angiography in seven patients, 11 to 48 months after cardiac transplantation. To delineate the importance of this problem, the risk factors and the therapeutic approaches in 7 patients who had ACA after heart transplantation were compared with those in 28 patients free of ACA at annual coronary angiography. Ischemic cardiomyopathy was the preoperative diagnosis in all but one patient in the ACA group. The age of the transplant recipients, total myocardial ischemic times and arterial blood pressures at follow-up were similar in both groups. Donor age averaged 31 +/- 3 years in the ACA group and 22 +/- 1 years in patients free of ACA. Preoperative cholesterol, triglyceride and high-density lipoprotein levels were lower in ACA-free patients and the low-density lipoprotein level was higher. At the last follow-up visit, serum lipid levels were similar in both groups. The incidence of acute rejection and of infection was slightly, but not significantly, higher in patients with ACA. The actuarial survival of ACA patients 4 years after transplantation was 30% +/- 20% compared with 100% for patients free of ACA (p less than 0.01). Actuarial rates of freedom from ACA and from death due to ACA were 73% +/- 11% and 81% +/- 11% respectively. Stepwise discriminant analysis showed that older donors and higher pretransplant triglyceride levels were independently related to the development of ACA after cardiac transplantation. In conclusion ACA remains an important cause of late death after heart transplantation. Although therapeutic measures are limited, prevention should focus on strict control of serum lipid levels after transplantation.

Adult↗
PubMed1991

[Percutaneous mitral valvuloplasty. An analysis of the immediate results].

Percutaneous mitral valvuloplasty (PMV) was performed by the anterograde transseptal approach in 113 patients with symptomatic mitral stenosis. Mean age was 53 +/- 14 years and 89% were female. PMV resulted in a marked decrease in mitral gradient from 16 +/- 5 to 6 +/- 3 mmHg (p less than 0.0001) and a significant increase in mitral valve area from 1.09 +/- 0.36 to 2.12 +/- 0.83 cm2 (p less than 0.0001). An optimal hemodynamic result (gain in valve area greater than or equal to 25% and post-PMV valve area greater than or equal to 1.5 cm2) was obtained in 82 patients (73%). Multivariate statistical analysis selected as independent predictors of an optimal result: normal cardiac index (p = 0.0001), NYHA functional class less than 3 (p = 0.002), smaller left atrial diameter (p = 0.005), and echocardiographic score less than or equal to 8 (p = 0.01). The lowest frequency of optimal results was observed in patients with echocardiographic scores greater than or equal to 11 (20%). Three patients died (2.6%). All deaths occurred among the first 34 patients and none in the last 79 (p less than 0.05). Morbidity was also influenced by a learning curve effect. Mitral regurgitation developed or increased in severity in 38% of patients. This increase was mild (1 degree) in 85% of cases. Although the incidence of atrial shunting was high (76% by indicator dilution curve and 33% by oximetry), their magnitude was usually small (mean Qp/Qs 1.23 +/- 0.23) and lacked clinical significance. In conclusion, PMV provides excellent immediate hemodynamic results with low mortality and morbidity risks, specially once experience has been gained with this technique. Patients with echocardiographic scores less than or equal to 8 and smaller left atrial diameters, usually younger and less symptomatic, are the best candidates for PMV.

Adult↗
PubMed1990

Left-to-right atrial shunting after percutaneous mitral valvuloplasty. Incidence and long-term hemodynamic follow-up.

To assess the incidence and long-term evolution of left-to-right atrial shunting (AS) after the performance of percutaneous mitral valvuloplasty (PMV), venovenous indicator dilution curves and right heart oximetric measurements were obtained in 68 consecutive patients before and after successful PMV. The procedure increased the mitral valve area (p less than 0.0001) and decreased the mitral gradient (p less than 0.0001). No AS was detected before PMV, but it was detected immediately after PMV. Oximetry identified AS in 17 patients (25%), and dilution curves identified AS in an additional 25 (total, 62%). The ratio of mean pulmonary to systemic blood flow (Qp/Qs) was 1.31 +/- 0.2, and in six patients (9%), the ratio was 1.5 or greater. Among nine clinical, 20 hemodynamic, and six procedural variables, stepwise logistic regression analysis selected the following as independent predictors of AS: smaller increases in valve area (p = 0.01) after PMV, absence of previous surgical commissurotomy (p = 0.02), mitral valve calcification (p = 0.02), and smaller left atria (p = 0.06). Among the 33 patients recatheterized at 6 months, oximetry had detected AS in 10, and dilution curves detected AS in an additional nine (total, 58%) immediately after PMV. At 6 months, AS had decreased or disappeared in 14 of these patients (74%), had increased in three (16%), and was unchanged in two (10%). Overall, at 6 months, oximetry identified AS in three patients, and dilution curves identified AS in an additional 13 (total, 48%). AS was detected at 6 months in only three patients but was not detected immediately after PMV. Although AS is very frequent immediately after PMV, Qp/Qs is usually less than 1.5. The appearance of shunting correlates with patient characteristics and with less improvement in valve area after PMV. Atrial shunting usually persists at 6 months, but its severity almost always decreases.

Blood Circulation↗
PubMed1990

[Coronary artery-right ventricular fistula in a patient with heart transplantation. A complication of endomyocardial biopsy].

Two cases of coronary artery right ventricular fistula were diagnosed during the yearly check-up of 38 of the 66 cardiac transplant patients of the Montreal Heart Institute between September 1982 and April 1989. In one case, the fistula involved the right anterior ventricular branch of the right coronary artery and in the other case, a septal branch of the left anterior descending artery. Histological examination of the biopsy fragments obtained before diagnosis of the fistula showed the presence of small calibre arteries, which was not the case in 10 control transplant patients. A review of the literature indicates that the risks of endomyocardial biopsy are minimal (less than or equal to 0.5%). However, the possibility of a coronary artery right ventricular fistula should be added to the list of known complications. The resulting shunt is negligible and has no haemodynamic consequences.

Adolescent↗
PubMed1989

Porcine versus pericardial bioprostheses: a comparison of late results in 1,593 patients.

From 1976 to 1988, 1,593 patients underwent valve replacement with a porcine (878 patients) or a pericardial bioprosthesis (715 patients). There were 701 aortic, 678 mitral, and 214 multiple-valve replacements. Follow-up was obtained for 1,559 patients (98%). Early mortality was 9% (79 patients) in the porcine valve group and 5% (37 patients) among patients with a pericardial valve (p less than 0.01). Late survival after replacement with porcine valves was 80% +/- 1% and 62% +/- 3% at 5 and 10 years, respectively. With pericardial valves, 5-year survival was 79% +/- 2%. Among valve-related complications, rates of freedom from thromboembolism, endocarditis, and hemorrhage after 6 years were similar for both valve groups. Freedom from reoperation at 6 years was also similar after aortic (96% versus 91%) or multiple-valve replacement (95% versus 88%). However, for mitral valve replacement, freedom from reoperation was significantly better with porcine valves than with pericardial valves at 6 years (92% versus 68%; p less than 0.001). This difference was mainly due to the Ionescu-Shiley valve, which accounted for 83% of primary tissue failures among pericardial bioprostheses implanted in the mitral position (10/12 patients). After 6 years, freedom from primary tissue failure of mitral valves was 92% +/- 2% with porcine and 70% +/- 11% with pericardial bioprostheses (p less than 0.0001). The degree of clinical improvement among survivors was similar with both valve types. Thus, in the aortic position, pericardial valves compare with porcine valves up to 6 years, whereas in the mitral position, the durability of the former is significantly less, mainly because of the suboptimal performance of the Ionescu-Shiley pericardial bioprosthesis.

Adolescent↗
PubMed1988

Lymphocyte subpopulation monitoring in cyclosporine-treated patients following heart transplantation.

Circulating lymphocyte subpopulations were studied in 18 consecutive patients treated with cyclosporine-prednisone immunosuppression during the first month following heart transplantation. Eleven patients showed no evidence of graft rejection. There were eight episodes of acute rejection demonstrated at endomyocardial biopsy in 7 patients. Three patients were treated with corticosteroids, 3 were treated with rabbit antithymocyte globulin (RATG), and 1 died before treatment (early mortality: 5.6%). Using the monoclonal antibody technique, 150 determinations of lymphocyte subpopulations were performed and were correlated with 72 endomyocardial biopsy specimens. Cyclosporine immunosuppression caused a significant (p less than 0.05) decrease in total lymphocyte count (38%) and in the number of OKT3 (52%) and OKT4 cells (55%). During acute rejection, total lymphocytes and OKT3, OKT4, and OKT8 cells all increased significantly, but the T4 to T8 ratio did not change significantly. Treatment of rejection with corticosteroids resulted in a moderate but not significant decrease in all T-cell types, whereas RATG caused a marked but not selective decrease in all T-cell groups. In conclusion, T cells decrease with cyclosporine immunosuppression and with treatment of rejection and increase at onset of rejection, but the T4 to T8 ratio has no predictive value for the diagnosis and severity of rejection, and the sensitivity of the method does not permit its use to assess the degree of immunosuppression with cyclosporine following heart transplantation.

Adolescent↗
PubMed1988

Aortic valve replacement with the Carpentier-Edwards pericardial bioprosthesis: clinical and hemodynamic results.

From 1981 to 1987, 189 patients underwent isolated aortic valve replacement with the Carpentier-Edwards bovine pericardial bioprosthesis. There were 9 early deaths (30-day mortality of 4.8%) and 18 late deaths (3.3% pt-yr). After 5 years, the actuarial survival rate was 81.9%. All patients but one were followed for an average of 37 months after operation, and follow-up totaled 551 patient-years. Valve-related complications included 12 thromboembolic episodes (2.2%/pt-yr), 7 endocarditis (1.3%/pt-yr), 2 hemorrhages due to anticoagulation (0.4%/pt-yr), and 3 reoperations (0.5%/pt-yr). After five years, freedom from thromboembolic events was 91%, that from reoperation was 98%, and 87% for all valve-related complications. There was no primary tissue failure of the valve. Before operation, 55% of the patients were in functional Class III or IV, 97% of the survivors were in Class I or II after valve replacement. Hematological evaluation of 77 patients, an average of 18 months postoperatively, showed no clinically significant hemolysis. Postoperative hemodynamic studies in 28 patients showed mean aortic pressure gradients across the prosthesis at rest ranging from 24 mmHg with the smaller (19 mm) to 11 mmHg with the larger (25 mm and more) valves, and effective orifice areas ranging from 1.0 to 1.9 cm2, respectively. Thus, the Carpentier-Edwards pericardial bioprosthesis appears to be a reliable and hemodynamically effective substitute for replacement of the aortic valve.

Adult↗
PubMed1987

Restenosis after successful percutaneous transluminal coronary angioplasty: the Montreal Heart Institute experience.

Repeat coronary angiography was performed within 6 months after successful percutaneous transluminal coronary angioplasty (PTCA) in 178 of our first 181 patients (98%). The remaining 3 patients were symptom free, had negative treadmill exercise test results and were considered not to have had restenosis. A second follow-up angiogram was performed in 107 patients (59%), including all patients with persistent or recurrent anginal symptoms, between 7 and 18 months after PTCA. Fifty-one of the 181 patients (28%) had restenosis on 51 of 205 successfully dilated segments (25%). The stenosis was greater than or equal to 70% in 49 of these 51 segments; it was 65% and 55%, respectively, in the 2 remaining patients. Restenosis was documented angiographically at a median time of 4.7 +/- 4 months. However, 47 patients (92%) had restenosis documented within 6 months, 2 between 7 and 12 months and 2 between 13 and 18 months after PTCA. Stepwise logistic regression analysis selected the following factors as independent predictors of restenosis after PTCA: variant angina, multivessel disease, severity of residual stenosis and less reduction in the diameter of the stenosis on the angiogram immediately after PTCA. Of these 4 factors, the degree of residual stenosis immediately after PTCA was by far the most significant. It is concluded that restenosis occurs in approximately 25% of patients, almost always within the first 6 months, after successful PTCA. The degree of residual stenosis after PTCA is the most important predictor of restenosis. Increased experience and improved instrumentation may eventually lead to less residual stenosis and better late results after PTCA.

Angioplasty, Balloon↗
PubMed1987

Design features of a controlled clinical trial to assess the effect of a calcium entry blocker upon the progression of coronary artery disease.

This report presents the design and methodological features of a double-blind, randomized, placebo-controlled, trial in 383 patients with coronary artery disease. The study's principal objective is to determine whether chronic treatment with a calcium entry blocker can retard the progression of coronary artery disease. The study population consists of patients with coronary artery disease and a baseline coronary arteriogram that qualifies them as being at high risk for disease progression. After satisfying all entry criteria, patients were randomized to receive either the calcium entry blocker nicardipine or placebo. All indicated concomitant medications except calcium entry blockers are permitted. Patients are being followed clinically for 24 months before undergoing a second coronary arteriogram. The effect of the treatments on a variety of clinical and angiographic parameters will be determined.

Adult↗
PubMed1986

[Evaluation of new pericardial bioprostheses by pulsed and continuous Doppler ultrasound ].

The authors have studied by pulsed and continuous Doppler ultrasonography 108 pericardial prostheses in a good functional state implanted for less than five years to patients without any clinical and echographic signs of heart failure. The pulsed Doppler ultrasonography allowed to exclude the possible dysfunction of the prostheses; continuous Doppler ultrasonography allowed the measurement of the maximal transprosthetic velocities and to deduce the corresponding maximal and middle gradients by means of simplified Bernouilli's equation. Using three types of bioprostheses (Carpentier-Edwards, Ionescu and Mitroflow) the following problems were investigated: Normal ranges of maximal transprosthetic velocity and gradients. At the aortic level the maximal velocity ranges from 1.60 to 2.83 +/- 14 m/s and the maximal gradients from 10 for size 27-29 to 32 +/- 3.3 mmHg for size 19. At the mitral level the maximal velocity ranges from 0.80 to 2 m/s and the mean gradients from 1 for size 33 to 7 mmHg for size 25. The mean half-life of decrease is 100 +/- 28 ms. Thus all aortic bioprostheses appear to be stenosing, which is not the case for the mitral ones, size 31 and 33. Factors governing the maximal transprosthetic velocity and the gradients: these determining factors are the size, the type and the age of the bioprosthesis (r = 0.59 for the correlation between maximal velocity and size, r = 0.53 between size and mean aortic gradient). The accessory factors are the age and the functional condition of the myocardium. All these factors have to be considered and neutralized for allowing a valid comparison of various types of prostheses. Comparison of the three pericardial prostheses studied: in patients without signs of myocardial dysfunction of prosthetic origin and with comparable basal conditions, comparison of maximal velocity and of the gradient points to a significant superiority of the Mitroflow at the aortic level and of the Ionescu and Mitroflow at the mitral level. It should be noted in the end that the great similarity of the results obtained in the present study by Doppler ultrasonography with the previously reported hemodynamic data confirms the important role of the Doppler method in the evaluation of valvular bioprostheses.

Adult↗
PubMed1986

[Dysfunction of bioprostheses. Respective value of echocardiography and of Doppler studies].

The respective diagnostic values of M mode and 2D echocardiography and pulsed and continuous wave Doppler were assessed in bioprosthetic valve dysfunction. The results of the ultrasonic investigations were compared with the operative findings and anatomo pathological appearances in 56 cases of dysfunction. Only cases with surgical confirmation were included. Doppler examinations were carried out in 13 cases. Echocardiographic imaging alone cannot resolve all the diagnostic problems posed: specific signs are rare and were only observed in one out of 7 cases of periprosthetic leak, 7 out of 10 cases of valvular stenosis and 20 out of 36 cases (55 per cent) of valve tear. In cases of valve tear, 2D echocardiography was falsely normal in 15 per cent of cases and gave equivocal results in 30 per cent of cases because it was not possible to visualise the three cusps of the bioprostheses. Doppler echocardiography does not have the same limitations and gives an immediate and accurate assessment of valve function. It is particularly useful for the diagnosis of stenosis and valve tear in which the diagnostic specificity and sensitivity attain 100 per cent (exact diagnosis in all 11 cases of valve tear). At present, continuous wave Doppler seems to be the most reliable diagnostic tool for qualitative and quantitative assessment of primary degeneration of valvular prostheses.

Adult↗
PubMed1986

[The surgical alternative in the treatment of terminal cardiomyopathies: cardiac transplantation].

Between April 1983 and November 1985, 14 patients have undergone a heart transplant, or 10 men and 4 women, aged from 17 to 55 years. The surgical indication was a cardiomyopathy in terminal evolutive phase, of which the etiology was ischemia in 8 cases, congestion in 5 cases and rheumatism in one case. There was one operative death (7.1%) from acute rejection and a late death secondary to chronic rejection. The actuarial rate of survival at one and 2 years was 81.9%. Post-operative complications, most frequent at an early stage, were arterial hypertension (9 cases), rejection (8 cases) and renal insufficiency (6 cases). During an average post-operative evolution of 13 months, 17 rejection episodes occurred in 10 patients (71.4%) and 5 patients (35.7%) presented with 7 infectious episodes, one of them severe. Cyclosporin's toxicity appeared in the immediate post-operative period by an always reversible increase of the bilirubin and creatinin levels. On a long term, all patients present with arterial hypertension, accompanied by a moderate renal insufficiency (creatinin between 2.2 and 2.4 mg%). Among the survivors, 9 patients (75%) remain completely asymptomatic and have resumed normal physical activities. Cardiac transplantation has therefore become a valid therapeutic alternative, able to greatly improve survival and the functional condition of patients with terminal cardiomyopathy.

Adolescent↗